The invention relates to an extrusion device for compacting metal shavings to form homogenous extrusion mouldings, with at least one extrusion unit with an extrusion die formed by a die housing, which forms a mould cavity, a guide arrangement for an extrusion element adjustable by a drive device, and with an inlet opening for the shavings in the die housing.
From FR 2,274,369 A a device for extruding profiles made of residues or waste from aluminium or aluminium alloys is known. Because of the extensive use of such profiles, many residues are produced which can be recycles by the method described in FR-A and the device for performing the method. According to this method and the corresponding device, the cut up waste is subjected to a comprehensive pretreatment of cleaning and a pre-moulding is made for use in a press cylinder, for which the waste is filled into a cage-like covering made of the same material as the waste. The thus produced pre-mouldings are then heated to the necessary temperature and extruded through a profile-producing die. The disadvantage here is the very expensive pretreatment to obtain the necessary high quality of thus produced profiles.
From U.S. Pat. No. 5,391,069 A a compaction device for producing compact pellets made of metal shavings is known with a hydraulically drive extrusion stamp in a compaction chamber into which a screw conveyor device opens to supply shavings from a container. The compaction chamber has on its front face a driven flat slide, by means of which the former is optionally closed or opened on its face end opposite the die stamp. The disadvantage of this device is that the extrusion force for compacting the shavings is uniaxial and takes place against a flat reaction surface formed by the slide, by means of which the homogeneity in the extrusion moulding differs greatly between the core and circumferential area.
The object of the invention is to create an extrusion device, which is characterised by a high productivity and product quality, and in which the finished extrusion mouldings have a low moisture content and a homogenous composition.
The object of the invention is achieved with an extrusion device of the first-described type, wherein the extrusion die forming a conically tapering compression channel with a die opening forming a passage surface for a material strand is arranged opposite an outside face of the extrusion element facing the mould cavity and adjacent to the mould cavity, and the passage surface is smaller than a cross sectional surface of the mould cavity. The surprising advantage here is that an extrusion device for the shavings to be compacted is created in which the shavings are pressed against an extrusion die and are pushed through an extrusion opening, the passage surface of which is smaller than a cross sectional surface of the extrusion housing, whereby a demoisturising and a homogenous plastification of the shavings to form a continuous strand is achieved, and a simple die structure is achieved, and a division of the die into less stressed components and highly stressed components subjected to a large degree of wear is achieved.
The object of the invention is also to create an arrangement which is characterised by high productivity and product quality, in which the finished extrusion mouldings have a low moisture content and a homogenous composition. In addition, the storage of the shavings in a spatially delimited area should be possible and an even feeding of the extrusion device should be achieved, regardless of any fluctuations in amount, on the further transport of the shavings.
This object of the invention is achieved with an arrangement for compacting metal shavings made of Al, Cu, Mg or alloys of these elements or other low melting metals or their alloys, with at least one conveyor device for the shavings arranged in a storage device, which conveyor device is connected with an extrusion device, which comprises at least one extrusion unit, each unit having extrusion dies and extrusion elements adjustable relative thereto by drive devices. The extrusion dies have cylindrical cavities which are delimited at least partly by the die housings and a bore axis of a preextrusion housing mounting a preextrusion stamp is arranged at right angles to a middle axis of a main extrusion die. At least one die housing has an extrusion die arranged opposite the drive device, which extrusion die forms a conically tapering compression channel with a die opening having a passage surface which is smaller than a cross sectional surface of the die cavity. The surprising advantage here is that a good demoisturising and a homogenous plastification of the shavings into extrusion mouldings is achieved.
An embodiment according to claim 29 is also possible in which the reduction in size is made possible with simple means and with little wear.
A variant according to claim 30 is advantageous in which the extrusion mouldings can be brought into a shape, in which they can be conveyed in a simple manner for further processing.
An embodiment variant according to claim 31 is advantageous, in which compaction is not performed by oscillating movements but by continual movements and thus by the reduction or removal of time cycles the productivity and also the product quality is increased.
The embodiment variant according to claim 32 has the advantage that an even increase in pressure and thereby a continual compaction and plastification is achieved.
The invention also relates to an arrangement as described in the preamble of claim 49.
The objective of the invention is also to create an arrangement which is characterised by high productivity and product quality, in which the finished extrusion mouldings have a low moisture content and a homogenous composition. In addition, the storage of the shavings in a spatially delimited area should be possible and an even feeding of the extrusion device should be achieved, regardless of any fluctuations in amount, on the further transport of the shavings.
The objective of the invention is achieved by the characterising features of claim 49. The surprising advantage here is that a good demoisturising and a homogenous plastification of the shavings into extrusion mouldings is achieved.
Developments according to claim 34 are advantageous, which have the advantages of claims 3 to 49.
An embodiment variant according to claim 35 is advantageous, by which it is possible to loosen the shavings and it is thus avoided that in the storage container, in particular in the transition area between the storage container and conveyor device, a so-called bridge is formed which would prevent the continual inflow of shavings from the storage container to the conveyor device.
The variant described in claim 36 has the advantage that required high torques can be achieved in a simple manner.
An embodiment variant according to claim 37 is possible, in which the loosening of the shavings in the storage container is achieved by simple means.
A further development according to claim 38 has the advantage that for example during repair work a complete emptying of the storage container is not necessary.
Claim 39 describes a robust, conveyor device that is not susceptible to breakdown and is characterised by a even conveying performance.
By means of the characteristic described in claim 40, a module construction of the arrangement is achieved surprisingly easily, whereby the necessary storage costs for spare parts are reduced.
An embodiment variant according to claim 41 is also advantageous, in which the conveyor means are subjected to a tensile load and thus a buckling of the conveyor means in the conveying state, i.e. in the loaded state, is prevented.
A development according to claim 42 is also advantageous, in which the metal parts or shavings are already dried during the transport.
By means of the characteristics described in claim 43 in a simple manner a sealed connection is created between the conveyor device and the extrusion unit.
The invention also relates to a method as described in the preamble of claim 50.
The objective of the invention is to create a method which combines the contradictory aims of increasing productivity and improving quality.
This objective of the invention is described by the characterising measures in claim 50. The surprising advantage here is that thereby the production of extrusion mouldings is achieved with a low moisture content and a high degree of purity and thereby a very homogenous composition. This makes it possible for the thus obtained extrusion mouldings to be fed to a melting process, to which only a low percentage of new materials have to be added in order to produce new parts and machine elements in a casting or injection moulding procedure, by means of which an economic utilisation of the shavings is achieved and the production of environmentally polluting special waste is avoided to a large degree.